The wide disparity on what lawmakers report about their income from public sources illustrates why we need clear, comprehensive, enforceable rules -- for the public's sake and the sake of public officials.

A recent report by The (Columbia) State newspaper found major differences in how lawmakers interpret the law's requirements and how they report their income and business interests.

The idea behind the requirements is to signal when lawmakers have a potential conflict of interest on an issue before the legislature. Given the way the law is written, the way it is interpreted and the way it is enforced (rarely, and only if someone complains), little light is shed in these required filings.

State Sen. Tom Davis of Beaufort is an exception. Davis reported in great detail about his property holdings, something most lawmakers are silent on, and included income his law firm earned from public sources.

Davis described the law as so "vague and general that it allows too much subjective interpretation by the lawmaker."

His answer was to err on the side of disclosure, reporting his $1.1 million home and other properties he owns because they benefit from public projects and services.

"That's the reason," Davis told the newspaper. "Whether I am right or not, I don't know."

If only other lawmakers took that approach. State Sen. Clementa Pinckney didn't even list his General Assembly salary ($10,400) or his in-district expenses allowance ($12,000) as most lawmakers did. If his General Assembly salary isn't income from a public source, what is? Is the law that open to interpretation? Pinckney was not alone in failing to report his legislative salary.

And there are other questions raised by lawmakers' filings. State Sen. Hugh Leatherman of Florence, chairman of the Senate Finance Committee, reported that he is a minority owner of the Florence Concrete Co., but didn't report that the state Department of Transportation awarded the company $735,000 in contracts in 2012. Leatherman said he didn't know or control what was happening with the company, so he had no reason to report its income from state contracts. But surely, as a minority owner, he benefited from those contracts.

As lawmakers move forward with ethics reform, they must answer the fundamental question of what should be accomplished with income reporting. If it is to identify potential conflicts of interest and shed light on officials' actions to ensure they don't use a public office for private gain, then a lot more should be asked of them than is asked now.

South Carolina is the only state that doesn't require public officials to report both public and private sources of income.

The S.C. Commission on Ethics Reform laid out a solid approach to income disclosure. The commission recommends that public officials disclose all private sources of income.

It also recommends that public officials disclose the amount they are paid by businesses that have contracts with or are regulated by the government. The same rules would apply to immediate family members.

Hand in glove with the problem of not adequately reporting sources of income is the lack of enforcement. The S.C. Ethics Commission, where the statements of economic interests from public officials across the state are filed, has three or four people to audit the 25,000 filings it gets every year, but they only audit a report when someone files a complaint, the commission's executive director says.

The House Ethics Committee has two part-time staff people to monitor reports from the 124 members of the House and challengers for their seats. The Senate Ethics Committee has one staff member to monitor reports filed by 46 senators and any challengers.

Leatherman says he wants the Ethics Commission to have enough people to look at every report filed, but a House budget proposal to increase registration fees by $100 was not included in the Senate budget, and negotiators, including Leatherman, killed the increase in the compromise budget, The State reports. The fees would have increased the Ethics Commission budget by $100,000. Nearly all of its $815,000 budget comes from fines and fees.

If lawmakers are serious about ethics reform, they're going to have to put money behind it. Rules mean little if they're not enforced.